SU1601679A1 - Overhead power transmission line - Google Patents

Abstract

The invention relates to electric power industry and can be used in overhead lines (VL) transmission lines to extinguish the wiring. The goal is to increase the reliability of the overhead line by preventing the overturning of eccentric loads during the course of a cable-carrying process or under other types of operational or climatic influences. Split phases use spacers with blind clamps. The spacers are located in the middle of the sections between the places of attachment of eccentric weights, which prevents the wire cross section at the locations of the struts and the possible tipping of the eccentric weights, leading to loss of their performance. This allows controlling the process of vertical and torsional oscillations of wires with eccentric weights. 2 Il.

Description

The invention relates to electric power industry and can be used in overhead transmission lines (VL) for extinguishing of wires.

The purpose of the invention is to increase the reliability of an overhead transmission line by preventing the overturning of eccentric loads during the course of plastics or other types of operational or climatic influences.

FIG. 1 shows a diagram of a bundle of wires of a split phase (pole) of a transmission line, top view, equipped with a system of eccentric weights and concentrated struts; in fig. 2-eccentric

the load, the moment of fixing on the wire and the working position.

Eccentric weights 2 and concentrated struts 3 are fixed on wire 1. Securing the fastening of concentrated struts divides the span of length L into sub-runs of length 1; (in this case of equal length, i.e. 1; 1), in the middle of each of which eccentric weights are installed on each of the wires of the split phase. Neighboring weights on each wire have centers of masses located on opposite sides of the axis held, and in each installation site of loads on adjacent wires are centers of masses of loads

05

Od

v |

located on opposite sides of the axes of the wires. The mass of the eccentric load, the eccentricity (center distance) to load the load from the wire axis e and the coordinate bi of the location of the eccentric load in the i-M sub-span of length Ij between the centered struts are chosen from

mgebj (li - biL „0) () 1 / -S2

where S is the torsional stiffness of the wire; the initial angle of inclination to the vertical of the eccentric load on the wire (figure 2), under which the load must be installed and secured, so that after it is lowered under the action of the moment of its own weight, it is placed in the horizontal, vertical position. Angle and / o must

have a value of order

Jl 20

and be on 30

It is placed in the same direction from the vertical plane as this eccentric load in the working (horizontal-25th) position.

The initial securing of the load in the specified position, provided that the CS / 0 angle is small, ensures its stability against tipping in all HVL operating modes.

On real overhead lines, the sub-span lengths between the struts can be 40–70 m. Eccentric weights may not be installed in each sub-fly. The number of installed loads is chosen from the condition that for a bundle of wires in a given span without danger, the band is limited by intensity attenuators with the number of half-waves n, where n is the number of spans equipped with absorbers

pl,

Power line works

next way.

When la wires lead to unilateral icy deposits and cross-directional wind acts on each of the wires 1, aerodynamic lifting force acts and the phase begins to swing in a vertical plane. When the wires 1 reach one of the extreme positions, for example, the lower one, the eccentric Hbie loads 2 twist the wires 1 in the middle of the proproles and the adjacent wires in each of the sub-flyings in opposite directions. 3 as a result of such tightening of adjacent areas

, five

0

0

five

35

40

45

The wires to the opposite sides of the aerodynamic forces acting on these areas turn out to be multidirectional. The lifting forces acting on the individual sections of the wire in the direction of motion are less in total than they could be in the absence of eccentric loads, which leads to a limitation of the amplitude of the pl. Concentrated struts 3 with blind clamps prevent excessively intensive twisting of wires with eccentric weights (at an angle of 90 ° from the working position of the load in a quiescent state). In the absence of struts or the use of struts with clips that allow torsion of the wire, it was possible such turns of wire 1 in the entire span of length L, at which tipping could occur: the part of the eccentric loads vani on the side opposite to the wire and their self-alignment in off-design inclined positions when they are restorations to extinguish pl SKU. .

The use of the invention makes it possible to increase the reliability of a system for blanking wires, and thereby working the entire line.

The work of a split-phase overhead transmission line consisting of 8 wires, 8 A.C 330/43, with a span of L 440 m, equipped with seven concentrated struts and 32 eccentric weights arranged in groups of B pieces in sections close to the middle of the sub-beams.

In order to prevent cargo collisions during various types of oscillations of wires (sub-oscillations, plate, etc.), it is advisable to install weights on adjacent beam wires with displacements in the longitudinal direction of about 1 m (Fig. 1). Mass of eccentric load m 4 kg, eccentricity e 150 mm, torsional rigidity of the wire, determined experiment

50 mentally, S 59

N. m glad

In this case, the angle of the initial installation of the load is on the wire (Vo, determined by the formula (1), is 0.1978 rad,, or 11 ° 20 relative to the vertical. The frequency of the first form of torsional vibrations of the wire in a subtrol of length 1 with a horizontal on the wire with eccentric weight,

51601

installed in the middle of the sub-span between the concentrated struts, is determined by the formula

one

a) .p f- (|

g 1

% i

SN (j)

(2)

where i is the linear moment of inertia of the wire, and I is the value determined by the equation

eleven

eleven

" one,

those

(

(3)

For wire AC 330/43, the linear moment of inertia is 0.757) S kgm, and dp of the considered example

4.63. 10 0.2135,

- (W

cr 6.8

glad

  1.082 Hz.

The frequencies of the first four forms of the vertical oscillations of the split phase (without taking into account suspended loads) are approximately according to the formula

1L

L

f

(four)

where L is the span length, is equal to 440 m, “n is the number of forms: vertical oscillations; T is the pull, which in this example is chosen equal to 25 kN; W is the linear mass of the wire, equal to 1.278 kg / m. According to the formula (4)

cJi 1 rad / s

032 2 rad / s-,

AEE 3 rad / s;

o) 4 4 rad / s;

. 0.159 Hz;

Goq

2TF

0.318 Hz;

| 0.477 Hz; fl 0.636 Hz.

6

A comparison of the frequencies of vertical oscillations of the span and the frequency of torsional oscillations of eccentric loads shows that the frequency of torsional vibrations of loads does not exceed the frequency of vertical phase oscillations for those considered. forms more than 6.8 times. So for the period of one

vertical oscillation of the wire The eccentric load with the sub-spin makes no more than 6.8 oscillations and the torsional oscillations will not attenuate completely due to the influence of self-damping of the oscillations of the wire and aerodynamic damping.

The technical efficiency of the invention is that due to the use in combination with eccentric weights of concentrated struts with blind clamps, the overturning of eccentric weights is excluded, which leads to the termination of their effective work on limiting plastics.

wires, as well as increased wire wear when twisted by tilting eccentric weights.

0

five

0

five

0

Claims (1)

Invention Formula An overhead transmission line containing split phases formed by bundles of wires fixed relative to each other by concentrated struts or groups of paired struts, eccentric weights rigidly fixed on each of the bundle wires, the centers of mass of which are; are located outside the vertical planes passing through the longitudinal axes of the wires, with adjacent goods on each wire, the centers of mass are located on opposite sides of the vertical plane passing through the longitudinal axis of this wire, characterized in that, in order to increase reliability by preventing tipping eccentric loads in the course of plastics wiring or other types of operational or climatic influences, the struts are made with blind clamps, and the ex-centric loads are installed in the middle of one space between struts. Fiz, 1